The New Jersey General Assembly is expected to vote on Thursday on whether to override Governor Chris Christie's veto of a gun safety bill, in what could be the first time the state's legislature has overturned a veto since he took office in 2010.

The state Senate already completed the first half of the override in October, when a handful of Republicans joined Democrats to reach the 27 votes needed in the 40-member chamber.

Christie, who is running for the 2016 Republican presidential nomination, vetoed the bill in August after it overwhelmingly in both legislative houses.

He has referred on the campaign trail to the fact that none of his vetoes have been overturned by the legislature.

The Senate vote was the first time either Democrat-controlled chamber had managed to override a Christie veto. Democrats, who control 48 of the Assembly's 80 seats, need 54 votes to complete the override and make the bill law.

Gun control has been a hot-button issue in the 2016 presidential race following deadly mass shootings in the United States, including one in Charleston, South Caroline, in June, when nine people died.

The legislation calls for police to be consulted when judges determine whether to expunge mental health records of prospective gun buyers.

Federal law prohibits the purchase of firearms by anyone who has been involuntarily committed to a mental health facility, but that record can be erased by a judge if the person is deemed unlikely to pose a public danger.

In vetoing the bill, Christie proposed alternative reforms, including a requirement that a person previously involuntarily committed demonstrate medical evidence of suitability to obtain a firearm.